1. Field
The present invention is directed to phosphoroamidodithionites, more particularly S,S-dialkyl-N-mono- and di-substituted phosphoroamidothionites and their use as insecticides and/or herbicides.
2. Description of the Invention
Compounds of the present invention may be represented by the formula ##STR2## wherein R.sub.1 and R.sub.2 are independently alkyl of 1 to 8 carbon atoms, preferably alkyl of 1 to 4 carbon atoms and more preferably alkyl of 3 to 4 carbon atoms, or alkenyl of 2 to 8 carbon atoms, preferably alkenyl of 2 to 4 carbon atoms, R.sub.3 is hydrogen or alkyl of 1 to 4 carbon atoms, R.sub.4 is hydrogen, alkyl of 1 to 4 carbon atoms, alkenyl of 2 to 4 carbon atoms, aryl of 6 to 15 carbon atoms substituted with 0 to 5 halogen atoms of atomic number 9 to 35 or alkyl groups of 1 to 4 carbon atoms, or an acyl group of 2 to 4 carbon atoms, with the proviso that R.sub.3 and R.sub.4 may be joined to form an alkylene radical of 2 to 5 carbon atoms, preferably 4 to 5 carbon atoms.
The aryl groups which R.sub.4 may represent are preferably benzyl or phenyl, either being substituted with 0 to 5 halogen atoms of atomic number 9 to 35 or alkyl groups of 1 to 4 carbon atoms. More preferably, R.sub.4 is phenyl substituted with 0 to 2 halogen atoms of atomic number 9 to 17 or alkyl of 1 to 2 carbon atoms, and still more preferably, phenyl substituted with 0 to 1 chlorine or fluorine atom.
Representative alkyl groups which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may represent include methyl, ethyl, n-propyl, isopropyl, butyl, t-butyl, etc. Representative alkenyl groups which R.sub.1, R.sub.2 and R.sub.4 may represent include vinyl, allyl, crotyl, etc. R.sub.1 and R.sub.2 may also be pentyl, hexyl, octyl, etc. Preferably R.sub.1 and R.sub.2 will be the same, or will be alkyl. R.sub.4 is preferably alkyl or aryl optionally substituted as the case may be.
Representative aryl groups which R.sub.4 may represent include phenyl, naphthyl, benzyl, o-chlorophenyl, o-fluorophenyl, o-bromophenyl, p-fluorophenyl, m-chlorophenyl, o-methylphenyl, p-butylphenyl, o-butylphenyl, o,p-dichlorophenyl, pentachlorophenyl, o-chloro-p-methylphenyl, o-fluoro-m-chlorophenyl, 2-chloronapthyl, etc.
Representative radicals which R.sub.3 and R.sub.4 joined together with nitrogen may represent include piperidyl, pyrrolidyl and morpholine.
Representative acyl groups which R.sub.4 may represent include acetyl, propionyl and butyryl.
Representative compounds of the present invention include S,S-dimethyl-N-butyl phosphoroamidodithionite, S,S,-dimethyl-N-phenyl phosphoroamidodithionite, S,S-diethyl-N,N-dimethyl phosphoroamidodithionite, S,S-dimethyl-N-acetyl phosphoroamidodithionite, S-methyl-S-ethyl-N-isopropyl phosphoroamidodithionite, S-methyl-S-ethyl-N-vinyl phosphoroamidodithionite, S,S-diethyl-N,N-diethyl phosphoroamidodithionite, S,S-diisopropyl-N-methyl phosphoroamidodithionite, S,S-n-butyl phosphoroamidodithionite, S-methyl-S-hexyl-N-ethyl-N-propionyl phosphoroamidodithionite, S-propyl-S-allyl-N-methyl-N-phenyl phosphoroamidodithionite, S-methyl-S-vinyl-N-methyl phosphoroamidodithionite, S,S-dipropyl-N-2-chlorophenyl phosphoroamidodithionite, S,S-dibutyl-N-2,4-dichlorophenyl phosphoroamidodithionite, S,S-dibutyl-N-2-ethylphenyl phosphoroamidodithionite, S,S-diethyl-N-ethyl-N-2-naphthyl phosphoroamidodithionite, S,S-dibutyl-N-pentachlorophosphoroamidodithionite, S,S-dibutyl-N-2,4-dichloro-3,5-dimethylphenyl phosphoroamidodithionite, S,S-dibutyl-N-piperidyl phosphoroamidodithionite, S,S-dibutyl-N-pyrrolidyl phosphoroamidodithionite, etc.
The compounds of the present invention are prepared by the reaction of an appropriate S,S-dialiphatic hydrocarbyl phosphorus halide with ammonia with a suitable amine or with an appropriate amide according to the following reaction: ##STR3## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as indicated above and X is a halogen, preferably chlorine.
Generally, the reaction is accomplished by adding the ammonia or amine slowly to the phosphorus chloride. Preferably an excess, e.g., up to twice the molar amount of ammonia, amide or the amine can be used. The excess reactant acts as a base acceptor to react with the evolved HX and thereby neutralize it. The reaction is preferably carried out in the presence of an inert solvent, such as methylene chloride ether, benzene, hexane, etc. Also a molecular seive is preferably present which serves as a drying agent for the solvent amine. The amount of molecular seive should be enough to assure substantially complete removal of any H.sub.2 O.
When ammonia is reacted with the phosphorus chloride it is generally preferable to dissolve the ammonia in the solvent and then add the phosphorus chloride to the ammonia-solvent mixture. When an amine is used, the solvent is preferably added to the phosphorus chloride and the amine added slowly to the phosphorus chloride-solvent mixture.
The above reaction is preferably carried out at a temperature from -78.degree. to 30.degree. C. Following the reaction, the product can be recovered by conventional means. Thus the reaction mixture may be stripped of solvent, the product washed with water and dried over magnesium sulfate.
The phosphorus chloride is known in the art and can be prepared as for example by the procedure in U.S. Pat. No. 3,210,244. Thus a suitable mercaptan may be reacted with phosphorus trichloride to give the S,S-dialiphatic hydrocarbyl phosphorus chloride. If different alkyl or alkenyl groups are desired, two different mercaptans can be reacted with the phosphorus trichloride.
The present invention can be more fully understood by reference to the following examples.